Liquid purifying filters, or in particular portable water filters used to purify water for drinking purposes in a remote location, have been in use for many years. In some cases, water purifying filters, such as an ultrafilter or a microfilter, have been incorporated as an inline filter with hydration packs containing a water bladder reservoir that is carried on one's back. In other cases, water filters might be a separately carried item whereby one dips or attaches the inlet of the water filter directly to a source of water to be purified.
In the situations described above, the filter must typically be primed to purge out air of a new filter before it can be effectively used. In some cases, a special air permeable membrane might be used as an aid to help air removal at first use, however these membranes can be costly and add complexity to the finished device. Also, use of an air permeable membrane to aid air removal during actual use makes it difficult to test filter integrity during manufacturing and when in use as many of these methods involve pressurized air to detect filter leaks. In other cases a vent port is included on the water filter such that it can be opened to purge air out of the upstream compartment then closed in order to operate the filter unit. This however, requires the inlet water feeding the filter to be under a positive pressure in order to push air out of the vent port of the filter. For inline filter configurations, one might need to somehow squeeze the water bladder or hydration pack to accomplish this task. This, however, generally requires the hydration pack to be removed from the person's back such that they can apply pressure to the pack, such as by sitting on the pack after opening the vent port. This can be cumbersome to the operator to perform. For stand-alone filters whereby the inlet port of the filter may be placed directly into a stream or lake source, one cannot simply increase the hydrostatic pressure of the inlet water and thus making it very difficult to prime and/or purge air out of the filter which can significantly reduce the flow rate through the filter. In these filter systems, it is common to use suction pressure created by the operator who attempts to suck water from the purified outlet side of the filter.
Also, once a portable filter is in use in the field, sediment and/or other particulate can accumulate on the upstream compartment of the filter which can lead to a plugging of the filter membrane and an a loss of filter flow performance. In these instances, current portable water purifier systems need to be cleaned repeatedly as part of routine maintenance procedures to keep it functioning as intended. In order to carry out these cleaning procedure, typically one must remove or disconnect the filter from the hydration pack or inlet source and then blow air into the purified outlet port of the filter which pushes the resident purified water backwards across the filter membrane as a means to purge out the accumulated particulate in the upstream compartment of the filter. For these cases, the purged fluid would need to exit out of the filter inlet ports. If, however, the filter is designed with a vent port on the filter housing as a means to provide a second port to purge out the accumulated particulate, one would need to open up the hydration pack to access this vent port and then orientate the pack in a suitable way during the blow back operation such that the purged fluid can exit to the external environment instead of flowing into the internal space between the bladder reservoir and the outer hydration carrier pack. It can be seen that these are highly manipulative operations to perform.
There is therefore a need to provide a system that overcomes the above deficiencies.